Stephen Sondheim’s lyrics to ‘America’ were substantially changed for the West Side Story screen adaption. There had been complaints that the Broadway version was too belittling to Puerto Ricans, in that the song mainly ridiculed Puerto Rico and Puerto Ricans. The movie lyrics emphasize the racism and discrimination that Puerto Ricans were subjected to in America.
The “America” sequence on stage was conceived as a duet between Anita and Rosalia. For the film, it was altered to be one between Anita and Bernardo.
In the scene on the roof before “America”, when the girls are mocking Bernardo’s speech, one of the girls say ,”We came with our hearts open”, one of the Sharks says, “You came with your pants open!” This line had to be changed to “You came with your mouth open,” for the movie because of censorship standards.
Jerome Robbins rehearsed with the dancers for three months before shooting began. Once location shooting began, however, he kept revising and revising his original choreography. The dancers all claimed that they had never worked so hard on a dance piece, and most of them at one point or another sustained injuries during shooting. Robbins completed four numbers – the Prologue, “Cool”, “I Feel Pretty” and “America” – before he was removed from the project.
Chita Rivera originated the role of Anita when West Side Story premiered at New York’s Winter Garden Theatre (September 26, 1957). Rita Moreno played Anita in the movie.
Moreno’s singing voice was dubbed by Betty Wand only for “A Boy Like That” since it was below her range. Moreno sang “America” and “Quintet” herself. – IMDB